Actually, what it does is this.
The modem will pick up as if you just did the receiver on the phone. So it could pick up any line that rings or if not ringing, the first free line. Basically it works line a phone without buttons.
The overall modem works, but lacks the features of putting someone on hold or actually picking up a line from hold because you couldn’t choice a button unless you picked up the receiver on the phone and pressed a button on it which kind of defeats the purpose.
The phone systems are actually designed to support a mixed environment of voice and faxes. So offhand, I would say, my current modem may be good enough, but perhaps maybe the software that would be lacked to mirror the button features?
An associate had worked at a call center where the phone line is connected through the computer (did auto dialing, allowed them to be put on hold, etc etc), so the technology is out there somewhere, just not sure what it is.